
\begin{tikzpicture}[scale=5]
  \coordinate[label=below:$B$] (B) at (1,0);
  \coordinate[label=below:$D$] (D) at (0,0);
  \coordinate[label=above:$A$] (A) at ($ (B)!1! -80:(D) $);
  \coordinate[label=above left:$E$] (E) at ($ (D)!1! 40:(B) $);
  \coordinate[label=below:$C$] (C) at ($ (A)!1! -20:(B) $);
  \draw (C) -- (A) -- (B) -- (D) -- (E);
  \draw[blue] (D) -- (C) -- (E);
\end{tikzpicture}
